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Frequently Asked Questions / Food Allergy Questions & Answers


FAQs Food Allergies: UCLA Food & Drug Allergy Care CenterHow big is the needle in my epinephrine autoinjector?
The needle length on the standard 0.3mg EpiPen auto-injectors is 5/8-inch (1.58cm) and the corresponding length of the 0.15mg EpiPen (aka EpiPen Jr) is 1/2-inch (1.27 cm) The needle length in the TwinJect is also 1/2-inch.

Will my child outgrow his or her food allergy?
Maybe. As many as 85 percent of children with milk, egg or soy allergy will eventually outgrow their allergy.  A much lower percentage (about 20 percent) outgrow peanut allergy. You should discuss the status of your child's food allergy with his or her allergist to see if there are signs that the allergy might be resolving.  Decreased reactions on skin tests and decreases in blood levels of serum-specific allergic antibody may indicate the allergy is resolving or that your child is developing tolerance to the problem food. If you think you or your child's food allergy is improving, or want to find out the status of the allergy, discuss this possibility with your allergist.

Is it safe for someone with peanut allergy to go on a plane or to baseball games or other places where peanuts are available?
Yes, in general, it is safe for people with peanut allergy to be in public areas where peanuts are served, if precautions are taken and medical supplies for accidental exposures are readily available. In particular, the largest risk, other than eating peanut, is from skin contact, so it is important to wipe down surfaces and avoid physical contact with anyone handling or eating peanuts. Advise those who may have handled peanuts to wash his or her hands before they have contact with individuals with peanut allergy.

However, rarely there are some people with such severe allergies to peanuts that even minute amounts of peanut can trigger reactions. These people may be at risk from inhaled exposure to peanut. In general, people that experience reactions from inhaled exposures have primarily skin reactions. Systemic or severe reactions are extremely rare and atypical. 
Is eczema/atopic dermatitis a food allergy?
Sometimes. Eczema or atopic dermatitis may be a manifestation of food allergy and/or may be associated with classic immediate food allergy. Food sensitivity is more common in children than adults with eczema, just as food allergies are more common in children. About a third of children with moderate-to-severe eczema experience acute worsening of their chronic rashes when they ingest trigger foods. Many people with eczema or atopic dermatitis do not have food allergies and don't benefit from elimination diets.

Do allergy shots (aka "desensitization" or "allergen-specific immunotherapy") work for food allergy?
At this point, we do not know if "desensitization" or "allergen-specific immunotherapy" is safe and effective for people with food allergies. When allergy shots have been attempted for food allergy, the rate of severe allergic reactions was too high to continue investigations.  More recently, investigations are focused on giving the same type of treatment by mouth. Although this appears safer, there continue to be high rates of anaphylaxis,, and for this reason the highest risk patients have not been studied. Finally, this treatment does not offer a cure to food allergy,  However, this treatment may enable some people to eat larger amounts of the  food before experiencing symptoms.

For these reasons, food desensitizations are currently considered high-risk, investigational research activities and not a standard part of the treatment of food allergy.  Safety considerations vary for each individual case, and may depend on the specific food. So far, it has not be studied enough to be used as part of general food allergy care. 

How can my child or I have a food allergy when no one else in the family has one?
Genetics are just one of the factors in the development of food and other allergies. Usually, but not always, food allergy occurs in families that have tendencies towards allergic conditions such as eczema, asthma, food allergy or seasonal allergies. We do not know why one member of the family may have food allergy when all others have environmental or seasonal allergies.

But even when there is no familial tendency towards allergies, food allergies can develop for reasons that are poorly understood, although our developed lifestyle is likely a determining factor. This is best illustrated by families that emigrate from less-developed areas that have a very low prevalence of allergic disease to more-developed nations. With this move, even without a change in genetics, there is a much higher rate of food allergy and other allergic conditions.

Are food allergy reactions always the same?
No. Although allergic reactions are reproducible, in that the same problem food will cause an allergic reaction each time it is eaten, many things can make reactions "worse than usual." Some of these factors have to do with the way the person with food allergy encounters the problem food, including the route (contact or ingestion), the amount and the type of preparation (i.e. raw, baked, boiled, roasted, etc.).

Some of these are things we do may not associate with food allergy such as exercise, alcohol, NSAIDS (non-steroid anti-inflammatory drugs, such as ibuprofen, aspirin or naproxen), colds and other infections, as well as other physical and emotional stressors

Also, the overall health of the person, including other allergic issues such as asthma, eczema or chronic sinus congestion, can also affect severity of reactions.

Can I have an allergic reaction on a skin test but be able to eat the food?
Yes, it is possible to have a skin test or blood test that demonstrates the presence of allergic antibody (IgE) to a particular food and not actually be allergic.

The presence of food-specific allergic antibody  (IgE) will cause inflammation on a skin test or an elevated lab value on the blood test but does not necessarily mean you have food allergy. Other parts of the immune system, including regulatory T cells, may suppress or inhibit the potential effects of these allergic antibodies (IgE).

In fact, when skin-prick or blood tests are given to people with non-specific symptoms and without proper indications, positive tests are associated with actual food allergy only half the time.

Is it true that people can die from food allergies?
Yes, every year people die from anaphylaxis to foods. When we look at the causes of fatal food allergy, we find that the problem is not that people don't know what they are allergic to, or how to avoid these foods. The main problem is delayed administration of epinephrine. Usually, the delay is because people do not have the medication with them and they don't get medical attention quickly enough.

That's why it is important to follow these three rules at all times: 1) always carry your epinephrine autoinjector with you, 2) tell people around you about your allergies and what they can do in the event of an emergency before problems happen, and 3) seek help as soon as you experience any symptoms of food allergy.

FAQs on food allergies: UCLA Food & Drug Allergy Care CenterAre food allergies increasing?
Yes, the Center for Disease Control and Prevention reported an 18 percent increase in the prevalence of food allergies in U.S. children,  from 3.3 percent in 1998 to 3.9 percent in 2008. Many other studies have shown an increase in food allergy in various populations. The  reasons for this increase are not completely known, and there are likely to be several factors. Link to discussion on food allergies. However, part of the apparent increase may be due to increased awareness and increased reporting.

How common are food allergies?
It depends on the source quoted. Studies that rely on self-report find higher rates of food allergy. Most recent studies predict that approximately 6 percent of children and 3 percent of adults in the U.S. have food allergy.  The prevalence of a self-reported allergy is closer to 10 percent. The reason for the discrepancies between these numbers is unclear and likely represents misconceptions about food allergy. A recent comprehensive review of all the existing data stated that the true prevalence of food allergy is more than 2 percent and less than 10 percent.

Are food allergies a cause of autism?
No, there are no scientific studies that demonstrate a causative association of food allergy and autism, although many children with autism have feeding problems. Adverse reactions to foods, including food intolerances and food allergy, may aggravate behavioral symptoms in children with autism or other behavioral disorders. Remember, food allergy and autism are both common problems and it is possible to have both conditions simultaneously. Also, as with food intolerance in general, symptoms attributed to food allergy are frequently not actually immune mediated. It is important to understand that behavioral symptoms can also be affected by many other causes of feeding problems.  For more information, please see a recent collaborative report from numerous experts in the fields of autism, gastrointestinal disease and food allergy published in Pediatrics 2010. An online version is available at

Why do I have to carry epinephrine if I am really careful and avoid the foods to which I am allergic?
Accidental exposures can happen through no fault of your own.  Food from restaurants or other sources outside of your own home may contain the food allergen or can be contaminated by contact with the problem food. People who are not specifically educated about reading labels can easily make mistakes, and they may not understand that your health and well-being are at risk. Additionally, allergic reactions can be unpredictable, and reactions may be more pronounced because of other issues going on with your health, or due to the amount or form of the food ingested. There is nothing more important than being fully prepared for accidental exposures.

Will I always have to carry an epinephrine auto-injector?
For now, the answer is yes, people who have severe food allergies should always carry epinephrine.  Severe complications arise from food allergy when the administration of epinephrine is delayed. Hopefully, one day there will be other treatments, but none of these are currently available.

Are vaccines safe if you have food allergies?
Current guidelines recommend that egg-allergic patients receive an influenza vaccine skin test before the influenza vaccine. Some recent studies suggest that dividing the vaccine into two separate  doses may be also be a safe option.

Several studies have documented the safety of measles and mumps vaccine (which are both grown in chick embryo tissue culture) in children with severe egg allergy. Therefore the new recommendations are that egg-allergic children receive routine vaccination without the use of special protocols or desensitization procedures.

Should my child with food allergies go to a special school?
School policies to reduce the accidental ingestions of an avoided food and to educate the staff and students about the signs and treatment of anaphylaxis significantly improve the health and safety of children with food allergies.  With school-wide policies and individualized healthcare plans, children at risk for anaphylaxis can have the opportunity to enjoy a safe and healthy learning environment. You can and should meet with the principal of the school and the school nurse at the beginning of the school year and review both the school policy and your child's specific needs.

What is the difference between food allergy and food intolerance?
Adverse reactions to foods are very common. Medically, we differentiate these reactions into those caused by the immune system and all other types of reactions.  Food allergies are caused by a specific, reproducible immune response to a particular structural aspect of a food. All other reactions are considered food intolerances. Food intolerances occur for a variety of reasons including enzyme deficiencies (e.g. lactose intolerance) or a toxic effect (e.g. food poisoning) and may exist for unknown reasons (e.g. irritable bowel syndrome.) The misperception of food intolerances as food allergies complicates the public perception of food allergies because, in general, people with food intolerances do not have acute health risks from contact with small amounts of a problem food.

Can seasonal allergies cause food allergies?
Oral allergy syndrome, or pollen-food allergy syndrome, is very common in people who have pollen allergies. People with this condition are allergic to a pollen and have reactions when they eat certain raw fruits or vegetables. The reaction is immediate and can cause itching, irritation and mild swelling of the lips, tongue, roof of the mouth and throat. It is a form of localized hives.  It is usually self-limited although about 1-2 percent of people with this condition may experience generalized reactions or anaphylaxis.

What is tolerance?
Tolerance, in the setting of food allergy, means that you can eat a food and not have an allergic reaction. Tolerance is a specific immune response that suppresses the evolution of allergic reactions to food proteins.. Therefore, specific allergic antibodies and other components of the allergic response may be present but there is a regulatory mechanism that prevents the allergy reaction.

Can my epinephrine auto-injector accidentally go off?
People have had accidents with auto-injectors. In 20 years,  there have been published reports of about  69 people who experienced accidental injections. Most of these  involved an injection in a finger or thumb. No one experienced permanent damage from the accidental injection.  Importantly, other recent investigations demonstrate that many people do not know how to use their auto-injectors correctly. To prevent these types of problems, it is essential to regularly review the appropriate techniques for injection with your allergist.